In recent years, there is a technique in which an input device called a touch panel or a touch sensor is attached on a display surface side of a display device, and in which an input position is detected and output when an input operation is performed by bringing an input tool such as a finger or a touch pen (also referred to as a stylus pen) close to or in contact with the touch panel. A display device having such a touch panel is widely used for not only computers but also portable information terminals such as mobile phones.
For example, Japanese Patent Application Laid-Open Publication No. 2015-64854 (Patent Document 1) describes a display device integrated with a touch screen in which a touch scan signal is applied to each of a plurality of driving electrodes via a signal wire.
For example, Japanese Patent Application Laid-Open Publication No. 2015-122057 (Patent Document 2) describes a display device integrated with a touch screen panel in which a touch driving signal is applied to all or some of a plurality of electrodes grouped into a plurality of electrode groups.